FIG. 1A and FIG. 1B show a conventional antenna arrangement 100 in the form of a subscriber identity module (SIM), with FIG. 1A showing the antenna arrangement 100 in a plan view and FIG. 1B showing the antenna arrangement 100 in a cross-sectional view.
The antenna arrangement 100 has a common support 116, with a front 110 of the support 116 holding a loop antenna 102 having a plurality of turns 104. In addition, a back 112 of the support 116 holds a contact array 106 having a plurality of contact pads 108. As FIG. 1B shows, an electric current flowing through the turns 104 of the loop antenna 102 results in a magnetic field being produced, the magnetic field lines 114 shown in FIG. 1B being intended to be understood merely by way of outline. However, it is possible to see that the magnetic field lines 114 are produced at an angle (essentially at right angles) to the plane that is formed by the loop antenna 102, and hence at an angle to the plane of the front 110 of the support 116. Accordingly, even just an externally produced magnetic field induces a sufficiently large electric current in the loop antenna 102 when the magnetic field lines of the externally produced magnetic field pass through a region within the turns 104 of the loop antenna 102 (subsequently also called the loop region) at an angle (essentially at right angles, then the maximal electric current is induced) to the plane that is formed by the loop antenna 102.
Within the context of near-field communication with a reader 200, this structure of the loop antenna 102 has a good level of performance when the antenna plane of an antenna 202 of the reader 200, which antenna provides the externally produced magnetic field 204 for the loop antenna 102, for example, is essentially parallel to the plane of the loop antenna 102 (see FIG. 2). The efficiency of the loop antenna 102 is adversely influenced to a considerable degree, however, when the loop antenna 102 is covered even just to some extent by metal, which in this case brings about a kind of shielding of the magnetic field.
FIG. 3 shows an arrangement 300 with a battery 302 and the antenna arrangement 100 from FIG. 1A and FIG. 1B, which is arranged on a printed circuit board 304 (that is produced to some extent from metal, for example), wherein the contact pads 108 of the contact array 106 are electrically conductively coupled to electrical contacts (not shown) of the printed circuit board 304 by means of electrically conductive connections 306 (for example by means of solder joints 306). As FIG. 3 shows, magnetic field lines 308 that are possibly produced are blocked by the metal-containing battery 302 and the metal of the printed circuit board 304, both of which act as a magnetic shield, which means that near-field communication between the reader 200 and the antenna arrangement 100 is no longer possible, for example.
FIG. 4 shows a conventional antenna 400 with a ferrite core 402 in a plan view. The ferrite core 402 of the antenna 400 has an elongate parallelepipedal structure and hence four longitudinal lateral faces 408 and two end faces 410. In addition, the antenna 400 has a plurality of turns 404 that are arranged, for example are wound, around the four longitudinal lateral faces 408 of the ferrite core 402. In addition, magnetic field lines 406 are schematically shown that to some extent run through the end faces 410 and inside the ferrite core 402 in the longitudinal direction thereof and outside the ferrite core 402 essentially elliptically.
FIG. 5 shows a conventional antenna arrangement 500 in the form of a subscriber identity module (SIM) in a plan view.
The antenna arrangement 500 has a common support 502, with a front of the support 502 holding an antenna 400, as shown in FIG. 4. In addition, a back of the support 502 holds a contact array 504 having a plurality of contact pads 506. The magnetic field formed by the antenna 400, or the magnetic field lines 406 of said magnetic field, run(s) essentially parallel to the plane of the front of the support 502, and said magnetic field essentially has no magnetic field lines that run at an angle to the plane of the front of the support 502. Hence, the magnetic field is formed essentially only in one direction, namely along the longitudinal lateral faces 408 of the ferrite core 402. In the case of the antenna arrangement 500 shown in FIG. 5, the ferrite core 402 has its longitudinal extent arranged parallel to the longitudinal extent of the support 502.
FIG. 6 shows another conventional antenna arrangement 600 in a plan view. The antenna arrangement 600 is essentially the same as the antenna arrangement 500 from FIG. 5 with the difference that in the case of the antenna arrangement 600 shown in FIG. 6 the ferrite core 402 has its longitudinal extent arranged at right angles to the longitudinal extent of the support 502.
FIG. 7 shows an arrangement 700 with a battery 702 and the antenna arrangement 400 from FIG. 4, which is arranged on a printed circuit board 704 (that is produced to some extent from metal, for example), wherein the contact pads 506 of the contact array 504 are electrically conductively coupled to electrical contacts (not shown) of the printed circuit board 704 by means of electrically conductive connections 706 (for example by means of solder joints 706). As FIG. 7 shows, magnetic field lines 406 that are possibly produced are also hardly blocked by the metal-containing battery 702 and the metal of the printed circuit board 704, both of which act as a magnetic shield, however, which means that in this case near-field communication (albeit relatively poor, but already improved in comparison with the arrangement shown in FIG. 3) between the reader 700 and the antenna arrangement 400 is possible.